Accuphase E-202 Restoration

[sanjib]

This Accuphase E-202 came to me is in the protection mode when powered on. With the right amp board removed came out of protection. Check the pre-amp section separately, one channel is good but the other one had considerable distortion.
After checking the right amp I found the culprit was the differential pair. Replacing those solved the problem and for the preamp, a good cleaning of switches brings both channels into working condition.

I found someone in there before me and replaced one main filter capacitor, one resistor in the power supply.
Now it is ready for restoration.
First is the power supply board
What has been replaced:

Q1,Q2,Q5 - 2SC1451 - KSC3503DSTU
Q3,Q4 - 2SC1746 - KSC1845FTA
Q6 - 2SA497 - KSA1220AYS
Q7 - 2SC1746 - KSC1845FTA
Q8 - 2SC497 - KSC2690AYS
Q9 - 2SC1382 - 2N4923G
Q10 - 2SA682 - 2N4920G
Q11 - 2SA856 - KSC992FTA

D1,2,3,4,5,13 - 1S1555 - 1N4148
D11,12 - SV-02 - 2X1N4148 in sereis

Heat stressed R7, 27, and 28 were replaced with the same value and higher wattage metal oxide resistors.

C1 - 100uF/10 - 100uf/25V (Bi-polar Axial Vihsay)
C2 - 10uF/25 - 10uF/35V (Elna Silmic II)
C4 - 100uF/63 - 100uF/100V (Axial Vishay)
C5 - 3.3uF/50 - 3.3uF/50 (Bi-polar Nichicon muse)
C6 - 2.2uF/50 - 2.2uF/50 (Bi-polar Nichicon muse)
C8 - 2.2uF/50 - 2.2uF/100 (Panasonic ECQ)
C13,14,15 - 100uF/100 100uF/100V (Axial Vishay)
C16,17 - 10uF/80 - 10uF/80 (Axial Vishay)
C19- 4.7uF/50 - 4.7uF/50 (Bi-polar Nichicon muse)
C23 - 1uF/63 - 1uF/100 (Panasonic ECQ)

Before:


After

 

[sanjib]

Main Amp board
What has been replaced:

Q1, Q2 - 2SA620 - Gain matched KSA992FTA
Q3 - 2SC1451 - KSC3503DSTU
Q5, Q7, Q8 not replaced
Q5 - 2SC1746 - KSC1845FTA
Q6 - 2SA856 - KSA992FTA
In this board, there is an extra transistor Q9 - 2SC1746 and replaced with KSC1845FTA.

D2, D3, D6 - 1S1555 - 1N4148
D4, D5 - 1S1553 - 1N4148

Thermistor TH1 - 5TP-31L - THERMISTOR NTC 1KOHM 3260K BEAD

R13 - 5.6K/3W - 5.6k/3W wire-wound Vishay resistor
R28 - 31 - 1ohm/3W - 1ohm/5W (Vishay wire-wound resistor)
VR1 - TRIMMER 100 OHM 0.5W PC PIN SIDE
VR2 - TRIMMER 5K OHM 0.5W PC PIN SIDE

C2 - 0.47uF/250 - 0.47uF/250 (Panasonic ECQ)
C3 - 100uF/10 - 100uF/16 (Axial Vishay)
C5 - 1uF/50 - 1uF/50 (Elna Silimic II)
C8 - 220uF/63 - 220uF/100 (Axial Vishay)

Before


After

 

[sanjib]

Tone Amp board:

Q5 - Q8 - 2SA620 - KSA992FTA (Each pair gain matched)

C1, C2 - 0.22uF/250 - 0.22uF/250 (Panasonic ECQ)
C9 - C12 - 22uF/35 - 22uF/50 (Panasonic FC)
C15, C16 - 0.1uF/250 - 0.1uF/250 (Panasonic ECQ)

Before

After

 

[sanjib]

Filter Amp Board:

Q1 - Q4 - 2SA776 - KSA992FTA

C9, C10, C15, C16 - 0.22uF/250 -0.22uF/250 (Panasonic ECQ)

Before:


After

 

[sanjib]

Equalizer Board:

Q1 - Q4, Q7, Q8 - 2SA856 - KSA992FTA (Q1-Q4 are gain matched)
Q5, Q6 - 2SC1746 - KSC1845FTA
Q9, Q10 - 2SC1451 - KSC3503DSTU

D1-D4 - 1S1555 - 1N4148

C1, C2, C15, C16 - 1uF/250 - 1uF/250 (Wima MKP4)
C3, C4 - 2.2uF/25 (Tanatalum) - 2.2uF/50 (Wima MKS2)
C5, C6 - 4.7uF/25 (Tanatalum) - 4.7uF/50 (Wima MKS2)
C19 - C22 - 10uF/50 -10uF/63 (Elna Silmic II)
C17, C18 - 220uF/16 - 220uF/25 (Panasonic FC)

Before


After

 

[sanjib]

Old output transistors are removed, the heat sink is cleaned and reinstalled with new mica and heat sink compound. 4 main filter capacitors are replaced with Nichicon Gold Tune 10000uF/63V. Dc offset and bias dialed in and ready to sing. Meter lights are replaced with LEDs, all knobs and faceplate is cleaned and polished.

Before


After

 

[mtflycaster]

Very nice. I've done a couple of these. Well worth the effort! It's the core of my vinyl system.